Errol Morris and David Hockney are revising perception. This month, Morris publishes his book Believing is Seeing, a study of the ways viewers interact with photography and make truth-claims based on what they see in photographs. Hockney is using a series of cameras to demonstrate to viewers that they can see more of the everyday world. He wants people to consider the question: “What can nine cameras do that one can’t?” Someone could take both Morris and Hockney’s projects as nothing more than acts reinforcing relativism. That would seem to be an impoverished view of two people trying to think carefully about how we see, and how little we see when we insist that we are seeing.